public class Day_9_1_另类加法 {

    public int addAB(int A, int B) {
        // write code here
        if(B != 0){
            int resault = A ^ B;
            int s = (A & B) << 1;
            return addAB(resault, s);
        }else {
            return A;
        }
    }
}
